Implementing RFID without disrupting already successful
bar code systems?
MIT Enterprise Forum Auto-ID & Sensing Solutions Group
MIT Stata Center 5 November 2012
Sprague Ackley
Intermec
Is there a trick to encoding my bar code data in RFID?
How did RFID data end up so different from bar code data?
How can my primary serialized bar code data be encoded directly into RFID?
Is there ever going to be a simple way to encode bar code data into RFID?
How did RFID data end up so different from bar code data?
Initially, RFID only encoded a unique set of bits, i.e. not specific letters and/or numbers
Later, users wanted to encode their own data Parallel developments ensued
– MIT Auto-ID labs à EPCglobal – ISO/IEC 15962
While chip technology marched on …
UHF Gen 2 has four memory banks (MB) MB01 encodes primary serialized identity MB11 encodes “user” data
– GS1 user data is the AIs – ISO user data is the DIs
MB01- Primary serialized identity
GS1 uses Electronic Product Code (EPC) – 96 bits (12 bytes), very space efficient – All numeric – Requires buying a “GS1 Company Prefix”
ISO uses 15962 – Variable in length, less space efficient – Can be alpha-numeric – Low or zero cost enterprise identification
MB11- Secondary “user” data
GS1 EPC Tag Data Standard (TDS) – Highly complex but efficient encoding method – Numbers and letters are separated, mapped
and compacted – Has IP ramifications
ISO/IEC 15962 – Very simple but less efficient method – Every character is 6 bits – Public domain IP
MB01àEPC from MIT Auto-ID labs
MIT scientists envisioned an “internet of things” where everything was unique
Part of their plan identified enterprises
EPCglobal from MIT Auto-ID labs
GS1 (then UCC) first joined, then bought Auto-ID Labs, then replaced enterprise identification with their own system (i.e. “Company Prefix” as used in EAN/UPC)
GS1 established an independent company which they called EPCglobal
EPCglobal
Early management actively resisted unifying EPC encoding with bar code
Method for encoding a unique item number broke GS1 rules in place for >25 years
Encoding methods actually prevented data in bar code symbols from being encoded in an RFID tag
GS1 now “fixing” the inconsistencies
EPC tag encoding overview
EPC is 12 bytes, e.g. in hex 30 30 25 7B F4 6D 5B 20 00 00 01 90
12 bytes is 96 bits 0011000000110000001001010111101111110100011011011011011001000000000000000000000000000011001000
0
Bits are counted and assigned meaning
EPC Header Filter Partition length:8 3 3 bits:00110000 001 100 (7-digits)
EPC tag encoding overview 00110000001100000010010101111011111101000110110110110110010000000000000000000000000000110010000
GS1 Company Prefix bit length (depends on Partition value):24 in this example bits:000010010101111011111101 digits:0614141 Indicator digit and Item Reference bit length:20 in this example bits:00011011011011011001 digits:112345 Note: GS1 Company Prefix can be 6 to 12 digits
EPC tag encoding overview
00110000001100000010010101111011111101000110110110110110010000000000000000000000000000110010000
Serial Number bit length:38 (fixed) bits:00000000000000000000000000000110010000 digits:400 EPC URI urn:epc:id:sgtin: 0614141.112345.400
Bar code to an EPC tag*
Bar code to an EPC tag*
*Note: the number of digits in the GS1 Company Prefix is not known
*The Partition Value must be determined
* Leading digits of the GTIN determine the partition value (e.g. compare with a database of GS1 Company Prefixes)
GS1 fixing the problem
2007 “60-Day Review” identified concerns about bar code / RFID interoperability
2008 GS1 Missing Identification Replacement (MIR) Guideline
2009 GS1 BarCodes & EPC Interoperability Requirements
2012 GSMP BC EPC Implementation Guideline
Result – a clear need for an offline tool
Length of Company Prefix tool
2012-08-23 First meeting of ad hoc to develop an offline tool
Each Member Organization (MO) has a different way of assigning numbers
The numbers which are assigned and not assigned must remain confidential
Early discussions point to an algorithm based on a “table of ranges” that can be downloaded into a portable device
MB01àISO/IEC 15962
First RFID data encoding standard
Developed with the idea that “RFID data was different” than bar code data
ISO/IEC 15962
An elaborate system of “Object IDs” was invented so each piece of data was addressable
Different encoding methods are flagged by an Application Family Identifier (AFI)
A particularly simple AFI (A1) is useful for encoding UII data
15962 AFI A1 encoding overview
UII = 25SUN043325711MH8031200000000001 – Where 25S is the UII Data Identifier (DI) – UN is the issuing agency ID – 043325711 is the enterprise ID – MH8031200000000001 is the item number and serial
number combination Each character is replaced by 6-bit ASCII The bits are grouped into bytes (32x6=192à24) Pad to a full byte if necessary with some or all of
the string “100000”
15962 AFI A1 encoding overview
Replace each character with 6-bit ASCII value
15962 AFI A1 encoding overview Group bits into bytes (8-bit groups) and convert
to hex
Insert AFI for final encoded data stream A1 CB 59 AA E3 0D 33 30 2D 77 C7 1D 20 E3 C0 F1 CB C0 30 E3 C0 30 E3 C0 31
Is it ever going to be simple to encode bar code data into RFID?
ISO à Application groups are adopting 15962 with AFI A1 to have a direct method of encoding bar code data in MB01
GS1 à Has an online method of determining the length of the GS1 Company Prefix using GEPIR (Global Electronic Party Information Register)
GS1 à Developing an offline tool that should lead to seamless data collection functionality
“Peace is at hand.” Henry Kissinger, 18 October 1969
The answers
How did RFID data end up so different from bar code data? Early proponents thought RFID would replace bar code so little effort was made to insure that they could work together.
How can my primary serialized bar code data be encoded directly into RFID? ISO – by using 15962 with an AFI of A1hex. GS1 - With the EPC TDS, a GEPIR utility, zero filling and a default filter bit setting.
Is there ever going to be a simple way to encode bar code data into RFID? Yes. The user community is not going to rest until there is.
The future
“It is difficult to make predictions - particularly about the future.”
(Confucius, Winston Churchill, Groucho Marx, 'Yogi' Berra and
several others: Nature 455, 729, 9 October 2008)
The future
It took almost 20 years for the bar code supermarket system to become ubiquitous and it will probably take about the same time for RFID to do the same
Applications changing from internal closed-systems to fully open systems are forcing more emphasis on data interchangeability
Within the next five years, application data will be data carrier independent
Implementing RFID without disrupting already successful
bar code systems?
MIT Enterprise Forum Auto-ID & Sensing Solutions Group
MIT Stata Center 5 November 2012
Sprague Ackley
Intermec
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